1. Field of the Invention
The present invention relates in general to electrochemical cells, and more particularly, to an electrochemical cell having a pre-passivated electrode. The present invention further relates to a process for fabricating the same.
2. Background Art
Lithium based electrochemical cells, such as lithium ion secondary batteries, have been known in the art for several years. Furthermore, passivated electrodes or electrodes having a solid electrolyte interface (SEI) for use in lithium based batteries have been recently explored. In accordance with conventional technology, passivation of the electrode occurs during the initial charge/discharge cycle by sacrificing a portion of the cell""s capacity to form the SEI, which, in turn, results in a battery having lowered capacity and coulombic efficiency.
It is therefore an object of the present invention to provide a lithium ion electrochemical cell that utilizes pre-passivated electrodes to remedy, among other things, the aforementioned detriments and/or complications.
It is also an object of the present invention to provide a process for fabricating a pre-passivated electrochemical cell that remedies the aforementioned detriments and/or complications.
These and other objects of the present invention will become apparent in light of the present Specification, Claims and Drawings.
The present invention is directed to a pre-passivated electrode for use in an electrochemical cell comprising: a) an uncharged current collecting substrate; b) an active material layer associated with the substrate; and c) a solid electrolyte interface layer associated with the active material layer.
In a preferred embodiment of the invention, the electrode further includes means for increasing the coulombic efficiency of an associated electrochemical cell relative to an electrochemical cell without the solid electrolyte interface layer. In this embodiment the coulombic efficiency increasing means comprises the solid electrolyte interface layer.
In another preferred embodiment of the invention, the electrode further includes means for increasing the capacity of an associated electrochemical cell relative to an electrochemical cell without the solid electrolyte interface layer. In this embodiment the capacity increasing means comprises the solid electrolyte interface layer.
Preferably the current collecting substrate comprises a metallic mesh and the active material layer preferably includes at least one carbonaceous particle.
The present invention is further directed to an electrochemical cell having a pre-passivated electrode comprising a first electrode and a second electrode wherein at least one of the first and second electrodes includes: a) an uncharged current collecting substrate; b) an active material layer associated with the substrate; and c) a solid electrolyte interface layer associated with the active material layer and an electrolyte associated with the first and second electrodes.
In a preferred embodiment of the invention, the electrochemical cell further includes means for increasing the coulombic efficiency of the electrochemical cell relative to an electrochemical cell without the solid electrolyte interface layer. In this embodiment the coulombic efficiency increasing means comprises the solid electrolyte interface layer.
In yet another preferred embodiment of the invention, the electrochemical cell further includes means for increasing the capacity of the electrochemical cell relative to an electrochemical cell without the solid electrolyte interface layer. In this embodiment the capacity increasing means comprises the solid electrolyte interface layer.
Preferably the current collecting substrate of at least one of the first and second electrodes comprises a metallic mesh and the active material layer preferably includes at least one carbonaceous particle.
The present invention is also directed to a process for manufacturing a pre-passivated electrode for use in an electrochemical cell comprising the steps of: a) dissolving a metal with at least one solvent; b) associating an active material with the at least one solvent having the dissolved metal; c) associating an additive with the active material, and, in turn, forming a solid electrolyte interface onto the active material; and d) associating the active material with a current collecting substrate.
In a preferred embodiment of the process, the step of dissolving the metal includes the step of dissolving lithium metal.
In another preferred embodiment of the process, the step of associating the active material with the at least one solvent includes the step of associating an active material having at least one carbonaceous particle.
In yet another preferred embodiment of the process, the step of associating the active material with the current collecting substrate includes the step of associating the active material with a metallic mesh.
Preferably the process further comprises the step of applying a primer to the current collecting substrate.
In another preferred embodiment of the invention, the process further comprises the steps of associating a second electrode and an electrolyte with the pre-passivated electrode.
The present invention is further directed to a process for manufacturing a pre-passivated electrode for use in an electrochemical cell comprising the steps of: a) dissolving a metal with at least one solvent; b) associating an active material with an additive; c) associating the active material associated with the additive with the metal dissolved in the at least one solvent, and, in turn, forming a solid electrolyte interface onto the active material; and d) associating the active material with a current collecting substrate.